Distance and depth finding



Jan. 21, 1936. E. E. TURNER, JR 2,028,174

DISTANCE AND DEPTH FINDING Filed July 29, 1929 10 6 5 1 k v 2 3 I I I Inf/enter Eda/x72 E Turner 07:

Patented Jan. 21, 1936 UNITED STATES PATENT OFFICE Y a 2,028,174 DISTANCE AND DEPTH FINDING Edwin E. Turner, In, West 'Roxbury, Mass., as-

signor to Submarine Signal Company, Boston, Mass., 'a. corporation of Maine Application July 29, 1929, Serial No. 381,971 7 Claims. (01. 171-386) The present invention relates to distance and depth measurement, andmore particularly to the systems, apparatus and methods employed in determining, depths and heights by transmitting a sound or compressional wave signal and measuring the time interval between the emission of the signal and the receipt of the impulse reflected from the object whose distance is to be measured.

Various modifications in the general systems and methods have been employed in measuring depths and distances in the manner above indicated with commercial success In the system, method and means used in the present invention, however, there is great utility 'in the simplification of the apparatus, the deit has been customary either to use an oscillator,

an impact striker, or an explosive charge. The

, oscillator takes a number of vibrations to build up a maximum vibration and then dies down slowly when'the power is cut off. This means that on very shallow depths, where very short signals are required, the oscillator has great difficulty in putting into the medium its maximum power.

Further, in depth measuring, the sound emitter is only required to. operate for a very small percentage of the entire time, sothat the average power supplied is very small. A- two kilowatt oscillator, therefore, operating for two-thousandths of a second only. has a possible energy source for a signal of about three foot-pounds, which is very little energy. v

This is the possible energy without taking into account the losses, which amount to about and the fact that the oscillator cannot be operated at fullpower on account of the time necessary to build up to a maximum vibration.

With an impact striker it is possible to deliver more energy to the medium, as the striker is first drawn up by a solenoid against a. spring and then released. The energy stored. in thespring is all given to the motion of the striker and the diaphragm of the striker is given alarge vibration.

In this way considerable more energy is given to the medium than with an oscillator with no larger power supply. However, the solenoid must have a sufficient force to overcome the spring tension, weight and friction in pulling upthe striker and must be of considerable size. In fact, it takes considerably-more current to pull up the striker than to hold it up after it has been-pulled up, and as a considerable leeway of power must be provided to insure proper operation, the impact striker may be large and demand a good deal of power. V

The explosivecharge, while providing suflicient 5 power, is undesirable from the point of view of safety, hard to handle and time properly, and creates poor acoustic reception, particularly in a water medium, because of the gases emitted. In the present invention a, sounding mecha- 10 nism is employed which is of the impact type, but operated in such a manner in connection with the entire system that the source of power necessary to operate the sound emitter is remarkably small and draws a practically uniform load at 15 all times.

In place of a series of contacts controlled by cams and timed so that the sound is emitted when the indicator passes zero on the scale, as is usually the system employed with the ordinary 20 solenoid type of depth sounder, the sounder controls the operation of the indicator whose position at the time of the arrival of the reflected signal gives the distance or depth. In this connection, a new type of indicator is employed, as 25 will be pointed out further on in the specification.

The invention is illustrated by the drawing, in which lt l'igure 1 shows a schematic view of the system, an

geigure 2 shows the details of the indicating 30 t In Figure 1 the sound is emitted by the diaphragm l, travels to the bottom of the ocean or the reflecting surface along the path 2, is reflect- 35 ed along 3 to the hydrophone 4. The diaphragm is operated by a striker 5 on the lever 6, pivoted at I, through the operation of the motor 8; The shaft 9 of the motor 8 has a worm gear ill at its end, meshing with the gear pin I2, as shown on its fiat face. The pin l2 comes in contact with the arm l3 of the lever and raises the arm against the spring M as the cam II is rotated by the motor through the worm gear ID. The speed of the gear ll is made low so that the force available against the spring is large and considerable energy may be stored, even though the motor 8 be a-fraction of an horse power.

Asthe arm I3 rises, it raises the contact switch H, which carries a 40 v The current passing through the coil l8 causes it and the indicator l9 mounted thereon to be drawn counter-clockwise to the left end of the scale against the uniform spring force 20, since the coil l8 as shown is in a magnetic field formed between the poles 2! and 22.

The contact between the electrodes l6 and I! is so timed that the indicator I9 is released as the hammer 5 strikes the diaphragm l. The indicator latravels at uniform speed as the sound travels to the reflecting surface and returns to the hydrophone d.

The signal, upon its return, operates the indicating circuit 23, which is the same circuit used in my copending application Serial No. 270,660, filed April 1'7, 1928, and which causes a rapid change in plate current in the tube 25. This induces a high voltage across the secondary of the transformer 26 and brings about the discharge of the indicating tube 21, causing a red or other colored glow, only for an instant, however. The point of the indicator l9 against taneous illumination becomes momentarily visible, as if it were still, and allows the operator or observer to read the depth or distance indication on the scale.

The tube 21 is shown in detail in Figure 2,.and is composed of a plate 29 and a wire 30 running parallel to one another through the crescent shaped tube. The plate 29 may have a coating of powdered mica or the like on the back side so that the front side may glow. This coating may be put on the side of the plate furthest from the wire, so that a uniform glow will be visible without the dark line of the wire appearing at all. The outside of the tube on the back may also be silvered to reflect the illumination against the indicator.

The wire 30 is connected to one side of the secondary of the transformer 26, while the plate 29 is connected to the other side.

Having now described my invention, I claim:

1. In a system for determining depths or distances in combination a sound producer, an electrical switch, a measuring scale having an initial position, an indicator, means for moving the indicator uniformly with respect to the scale from the initial position, means operable by the electrical switch to restore and hold the indicator in its initial position, and means operable by the sound producer to operate the electrical switch whereby the closing of the switch takes place just before the sound production and the release of the indicator simultaneously with the sound production.

2. In a system for determining depths or dis tances in combination a sound producer, a measuring scale having cator having a constant velocity relative to the scale during the time measurement for indicating the depth, means for commencing the operation of the indicator simultaneously with the sound production, including electric means for initially restoring the indicator to the zero position of the scale and retaining it there comprising, an electric switch, means operable by the sound producer for operating said switch and means operable by the switch to restore and hold the indicator, the said means operable by the sound producer operating the switch, closing the same 'just before the sound production and opening it simultaneously therewith and means associated with the indicator for producing an indication upon receipt of the echo while the indicator is in motion.

this instanmechanically moving parts, a

a zero position, an indi-' 3. In a system for determining depth or distances in combination, a sound producer having mechanically moving parts, an indicator associated with a measuring scale having relatively stationary and movable elements, means adapted to move said movable element with respect to the scale, switching means operated directly by the mechanical parts of said sound producer and electrodynamic' means deenergized by said switching means for allowing. the means adapted to move the movable element to operate.

4. In a system for determining depths or distances, in combination with a sound producer, an indicating device having a measuring scale having an initial position from which measurements are to be made, an indicator adapted to com- 'mence the measurementof depths or distances from said initial position of the scale, spring means for propelling said indicator relative to said scale, means including an electric switch operated in the operation of said sound producer to restore the indicator to said initial position before the production of the sound to hold the indicator in said initial position until the production of the sound and to release said indicator upon the production of the sound.

5. In a system for determining depths or distances, in combination, a sound producer having measuring scale, an indicator associated therewith, said indicator having relatively stationary and movable elements, means adapted to move said movable element with respect to the scale, means operated by contact with the said moving parts for releasing said movable element, means associated with the stationary element of said indicator for producing an indication withreference to the scale and the movable element and means including the means for releasing the movable element to operate to restore the indicator to an initial position with respect to the scale.

6. In a system for determining depths or distances in combination, a sound producer having mechanically moving parts including an arm operated at the time ,of the production of the sound waves and a contact operated by said arm, a measuring scale, an indicator associated with a measuring scale having relatively stationary and movable elements, means adapted to move said movable element with respect to the scale, means operated by said contact for releasing said movable element, means associated with the stationary element of said indicator for producing an indication with reference to the scale and the movable element and means including the means for releasing the movable element to operate to restore the indicator to an initial position with respect to the scale.

7. In a system for determining depths or distances in combination, a sound producer, a measuring scale, an indicator associated with a measuring scale having relatively stationary and movable elements, a spring, means mounting said spring to exert a tension on the movable element in one position, an electrical coil fixed with said movable element, and means forming a magnetic field positioned to pull the movable element to said one position when the coil is energized, an electric switch operated directly by the sound producer for deenergizing the coil when the switch is open and energizing it when the switch is closed.

EDWIN E. TURNER, JR. 

